No endocrine gland has been subjected to more fruitful study during recent years than the thyroid. The availability of radioactive iodine, in particular, has stimulated numerous studies, which have added immensely to our knowledge of this gland. Although primarily of general physiological interest, these recent studies have clinical importance, since they throw light on many aspects of thyroid disorders. Dr. McGavack and his collaborators have done an excellent job in collecting the extant data on the thyroid and applying this information to clinical problems. The monograph is complete in its coverage, well written, and documented with many references to the literature. It can be recommended to the reader desirous of a résumé of recent work in the field.